SALEM, Ore. -- Attorney General John Kroger is warning consumers to avoid misleading and possibly illegal promotions for "free gas" and "free groceries."

The promotions are designed to get consumers to buy products they might not otherwise purchase. They typically offer hundreds of dollars of free groceries or gas if you buy certain products and mail in your receipts. There's often a $5 registration fee.

The scammer sometimes sends the first payment to encourage the consumer to continue to participate. But future rewards don't appear even though consumers continue to buy the product and mail in their receipts.

The Oregon Department of Justice is participating in a national crackdown of such false promotions and has warned Oregon retailers that these offers could be false and illegal.